A “touchscreen” is a display that can detect the presence and location of a touch, e.g., by a finger, within the display area. Touchscreen capabilities can be enabled by a range of technologies including resistive, surface acoustic wave, capacitive, infrared, strain gage, diffused laser imaging, optical imaging, dispersive signal technology, and acoustic pulse recognition. A touchscreen allows user input without requiring a separate device such as a mouse or trackpad. Unlike those devices, a touchscreen enables a user to interact with what is displayed directly on the screen, where it is displayed, rather than indirectly.
Touchscreens are incorporated increasingly in small devices such as cell phones, PDAs, digital audio players, and navigation units. Large touchscreen displays are also increasingly common in kiosks and other commercial settings. However, displays for desktop computers usually do not provide touchscreen capabilities.
TouchSmart™ computers, available from Hewlett-Packard Company, are notable exceptions. The computers include and are visually dominated by a touchscreen display. Infrared emitters at the upper corners of the display radiate light that is normally reflected by opposing display bezels. Linear detector arrays detect the reflections and any shadows to locate a touch trigonometrically. The touchscreen capabilities add significantly to the cost of the computers.
These figures depict implementations/embodiments of the invention and not of the invention itself.